Electrode feeding mechanism for arc searchlights



ELECTRODE FEEDING MECHANISM FOR ARC SEAR CHLIGHTS Filed July 17, 1937 WITNESSES: m7y%% c. F. HERBOLD 2,189,605 a Patented Feb. 6, 1940 UNITEDSTATES PATENT OFFICE ELECTRODE FEEDING MECHANISM FOR ARC SEARGHLIGHTS Carl F. Herbold, Lakewood, Ohio, assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 17, 1937, Serial No. 154,253 9 Claims. (Cl. 176-41) trode of an arc Searchlight having an electromagnetically operated device for causing the mechanism to feed the electrode with a circuit for energizing the electromagnetically operated device intermittently at a substantially constant rate. Means are provided for varying the length of the periods of energization of the electromagnetically operated device at will.

A thermostatically controlled circuit is also provided for energizing the electromagnetically operl0 ated device in response to the positioning of the arcing tip of the electrode. Means are provided for selectively placing the electromagnetically operated feeding control under the control of the. thermostatically operated circuit or the constant feed circuit.

Referring to the My invention relates, generally, to arc search lights and, particularly, to improvements in electrode feeding mechanisms for are searchlights.

In the operation of arc searchlights, it is necessary that the arcing tip of the positive electrode be maintained at, or very near to, the focal point of the reflector of the Searchlight so that the most efficient beam may be produced.

Because the positive electrode burns away very rapidly, it is necessary that some means be provided for feeding the positive electrode to the arc to compensate for the consumption of the electrode in the arc.

It is common practice to cause the positive electrode to move toward the arc in response to electromagnetic devices which are controlled by thermostatic circuit controllers actuated by the heat from the electrode tip and so positioned as. to be actuated when the electrode tip has receded a predetermined amount from the desired position. Such a device is shown in the patent to A. P. Davis, 1,433,073, October 24, 1922.

The object of my invention is to provide a feeding mechanism for the positive electrode of an arc searchlight which shall function to feed the electrode at a constant rate which may be adjusted to compensate for consumption of the electrode in the arc.

Another object of the invention is to provide a feeding mechanism for an electrode of an arc sear'chlight which may be caused to feed the electrode either automatically in response to the positioning of the arcing tip of the electrode, or continuously at a predetermined constant rate.

Another object of the invention is to provide an improved electrically controlled system for feeding an electrode of an arc searchlight.

These and other objects of the invention will be apparent from the following detailed description taken in connection with the accompanying drawing of which,

Figure l is a diagrammatic illustration of an electrode feeding mechanism for arc searchlights as embodied in the teachings of the invention.

Fig. 2 is an enlarged sectional view of the gear mechanism of Fig. 1.

Fig. 3 is an enlarged longitudinal sectional view of the control drum of Fig. 1 with the adjustable brush in contact with the contact strip on the drum, and

Fig. 4 is an enlarged sectional view of the control drum of Fig. l with the drum rotated 90 from the position of the section of Fig. 3.

drawing, the positive and negative electrodes 2 and 3 are energized from the source of current XY through conductors 4 and 5, respectively. The positive electrode is constantly rotated by a mechanism similar to that disclosed in the copending application of William H. Jacobs et al., Serial No. 43,372, filed October 3, 1935, now Patent No. 2,177,888, having a common assignee with this application. This rotating mechanism comprises rollers 6 and I which are made to bear upon the electrode by tension of the spring 8 and which are hinged on the head piece 9.

The head piece 9 is rotated through c tion with gear I!) which is driven by a mo through shaft l2 and pinion l3. By this mechanism, the positive electrode is continuously rotated while the motor II is energized.

The movement of the positive electrode toward. the negative electrode to compensate for consumption of the positive electrode in the arc is accomplished by a mechanism which comprises a worm I4 which acts upon a worm wheel mechanically connected with roller 1 to provide rotation of roller I which, in turn, causes a movement of the positive electrode. The worm I4 is connected with gear l6 through shaft l5 and is driven by gear I! when there is relative motion between the gear I! and the head 9. A ring l8 having a series of protuberances 39 on its periphery is secured to gear l1 and both gears I1 and ring l8 are mounted for rotation upon the sleeve l9 which connects the head 9 with the bevel gear Hi.

In the normal operation of the mechanism to rotate the electrode there is no relative rotation between the gear I1 and the head 9, since the gear I1 is made to rotate with the head 9, the gear I! being carried around by its contact with gear 16. It will be seen that while the head onnec In carrying out my invention, I provide a mechanismior continuously rotating the positive elector ll 30 9 is rotated, if the rotation of the gear I1 is stopped, gear IE will roll upon the periphery of gear i! and this will cause rotation of worm M which, in turn, will cause roller 1 to rotate to produce a feeding movement of the electrode 2.

The stopping of the gear IT to cause feeding movement of the electrode 2 is effected by the movement of detent 2! to form a stop for one of the protuberances 39 of ring I8. The movement of detent 283 to its positionin engagement with the ring I8 is produced by a solenoid 2|. Thus, it will be seen that the electrode 2 is continuously rotating and is moved toward the negative elecdrum there is disposed trode only while the solenoid 2| is energized.

The energization of the solenoid 2| is governed by the controller 22 in cooperation with the thermostat 23. The controller 22 comprises a drum of insulating material 24 which is continuously driven by a motor I through shaft 36and cooperating gears 3'! and 38. On the surface of the a metallic contact ring 25 of uniform width and a metallic contact ring Patent No. 2,162,524 issued June 13,1939,

brushv 36 is so positioned as to continuously en- 25 which has a substantially triangular segment ,21 extending therefrom along the drum surface.

A fixed brush member 28 is positioned to continuouslyengage ring 26 and a second fixed brush member 29. is positioned the ring 25. A third brush member 35.! is so mounted as to be movable axially of, and to remain in contact with, the drum surface.

The thermostat may be of any suitable type so positioned as to close its contact members when the arc tip of the'electrode 2 has receded from its desired position a predetermined amount, and may besuch an arrangement as co-pending application of P. H. Serial No. 130,740, filed March Brace et al., 13, 1937, now When gage ring 25, the detent solenoid 2| will be energized to cause feeding of the electrode 2 toward the. positive electrode when the thermostat 23 is closed through a circuit which extends from conductor X through conductor 3|, relay. 2|, conductor 32, brush 38, ring 25, brush 29, conductor 33, contact members of thermostat 23 and consolenoid 2|, conductor ductor 34 to the conductor Y.

When the movable brush 36 is so positioned as to engage the conducting segment 2? as it is rotated with the drum, the positive electrode 2 will be fed toward the negative electrode by energization of solenoid 2| through a circuit which extends from conductor X, through conductor 3|, 32, brush 3!], segment 2?, brush 28 and conductor 35 to conductor Y.

In the operation of the device, when it is de sired to control the feeding of the positive. electrode tothe arc in response to a predetermined movement of the electrode tip from its desired position, brushed is moved to a position to continuously engage ring 25 as the drum rotates, and solenoid 2| acts to cause movement of the positive electrode so long as the electrode tip remains in such a position as to causethe thermostat 23 toholds its contact members closed. When the arcing tip of positive electrode 2 has vanced to Where the heat from the electrode tip no longer aiTects the thermostat '23, the feeding of the electrode is stopped by deenergization of the circuitthrough solenoid 2| by opening of the contact members of the thermostat.

In the event of failure of the thermostat 23 to function properly or in the event that it should be found desirable to feed the positive electrode toward the negative electrode at a preto continuously engage shown in the said drum and disposed been adon each revolution of the drum 24. The brush may be so positioned as to make the periods of energization of the solenoid 2| such as to cause the feeding ofthe positive electrode 2 at a rate which will just compensate for the rate of consumption of the electrode in the arc and which will thus maintain the arcing tip of the electrode 2.2 substantially continuously in its desired position. i

It will be seen that I have provided a mechanism which is simple and reliable in operation and inexpensivev of manufacture, which will function to maintain the arcing tip of the positive electrode of an arc Searchlight in a predetermined w position either in response to a predetermined recession of the arcing tip due to consumption of the electrode in the are or continuously at an adjustable rate corresponding to the rate of consumption cf the electrode in the arc.

In compliance with the requirements of the 'patentstatutes, I have shown and described herein a preferred embodiment of my invention. It

is to be understood, however, that the invention is not limited to the precise construction shown and described, but iscapable of modification by one skilled in the art, the embodiments herein shownbeing merely illustrativeof the principles of my invention.

I claim as my invention: I

1. In an electrode feeding device having an electromagnetic actuating mechanism, means for intermittently energizing the actuating mechanism comprising a circuit and an interrupter for said circuit, said interrupter comprising a .rotat ing non-conducting drum, a conducting strip mounted on said drum, said strip increasing. in length from one end to the other and extending axially of said drum, brush means bearing on to intermittently complete said circuit, said brush means being movable axially of the drum to vary the interval of contact engagement with said strip as the drum rotates.

2. Ina feeding mechanism for an arc searchlight electrode, a controller comprising a rotatable drum having an electrically conducting band thereon,'a substantially triangular shaped electrically conducting segment extending axially said band, brush means engaging said band,-a second brushmeans engaging said drum and movable axially along as to vary the. duration of brush with said triangular said drum surface so contact of said second said band, brush shaped segment as said drum rotates, means for continuously rotating the electrode, electromagnetic means connected with said controller and cooperating with said rotating means for feeding said electrode, and means whereby said controller is rotated by said rotating means.

4. In a feeding mechanism for an arc searchlight electrode, a controller comprising a rotatable drum having a pair of spaced electrically conducing bands thereon, a substantially triangular shaped electrically conducting segment extending axially along said drum surface from one of said bands, brush means engaging each of said hands, brush means engaging said drum and movable axially along said drum surface, to vary the duration or contact of said slidable brush with said triangular shaped segment as said drum rotates and to contact either of said bands.

5. In an electrode feeding mechanism for an arc searchlight, means for continuously rotating the electrode, electromagnetically operated means cooperating with said rotating means for feeding said electrode, and means for selectively energizing said electromagnetic means either in response to the positioning of the electrode tip or intermittently at a predetermined rate, said energizing means comprising a rotatable drum having a pair of spaced electrically conducting bands thereon, a substantially triangular shaped electrically conducting segment extending axially along said drum surface from one of said bands, brush means bearing on each of said bands, brush means bearing on said drum and slidable axially along said drum surface to vary the duration of contact of said slidable brush with said triangular segment as said drum rotates and to contact either of said bands, circuit means whereby said electromagnetic means is energized directly when said slidable brush is positioned to engage said triangular segment or its associated band and through a switching device which is responsive to the positioning of the electrode tip when the slidalole brush is in contact with said second band, and means whereby said electrode rotating means also rotates said drum.

6. In an electrode feeding mechanism for an arc Searchlight, means for continuously rotating the electrode, electromagnetically operated means cooperating with said rotating means for feeding the electrode, an energizing circuit for said electromagnetically operated means, including circuit interrupter means continuously driven by said rotating means for intermittently closing said energizing circuit, auxiliary circuit control means for said energizing circuit, controlled by the positioning of the arcing tip of the electrode, and means including a portion of said circuit interrupter means for selectively rendering said circuit interrupter means and said auxiliary circult control means effective to control said energizing circuit.

7. In an electrode feeding mechanism for an arc searchlight, means for continuously rotating the electrode, electromagnetically operated means cooperating with said rotating means for feeding the electrode, an energizing circuit for said electromagnetically operated means, includ ll'lg circuit interrupter means continuously driven by said rotating means for intermittently closing said energizing circuit, auxiliary circuit control means for said energizing circuit controlled by the positioning of the arcing tip of the electrode, and relatively adjustable means including a portion of said circuit interrupter means for selectively rendering said circuit interrupter means said auxiliary circuit control means efiective to control said energizing circuit and for varying the length of the periods of closure of said energizing circuit by said circuit interrupter means.

8. In an electrode control system for a lighting device having arcing electrodes, means for feeding an electrode, main control means for causin said feeding means to feed the electrode at a substantially constant rate, supplemental control means for causing said feeding means to feed the electrode in response to the positioning of the electrode arcing tip, and selectively operable auxiliary circuit control means for selecting for operation said main control means and said supplemental control means.

9. In an electrode control system for a lighting device having arcing electrodes, means for feeding an electrode, main control means for causing said feeding means to feed the electrode at a substantially constant rate, supplemental control means for causing said feeding means to feed the electrode in response to the positioning of the electrode arcing tip, and adjustable selectively operable auxiliary circuit control means for selecting for operation said main control means and said supplemental control means and for varying the rate of feed controlled by said main control means.

CARL. F. HERBOLD. 

